Flat earther, conspiracy theory, good/bad faith, etc...simple memes like this are very effective in controlling both dumb and normatively "smart" people with simple rhetoric.
>>mister+(OP)
It's an ad hominem attack a lot of times. Calling RFK an anti vaxxer for example. He's much different than a person that flat out refuses all vaccines. But it's very effective to call him that and shut off all engagement with any aspects of his critique.